RELATIONSHIP BETWEEN WATER DEPTH AND PRESSURE IN MICRO-DAMS IN NORTHERN GHANA

Abstract

The availability and access to fresh water in sufficient quantities for domestic and productive purposes is and important aspect of improving livelihoods especially in the rural area. It is for this reason that small dam development in the savannah area of Ghana has become very important as they have a direct link in reducing high incidence of poverty in these areas. Variation of water levels in there water holding structures and the relationship of this variation on the water pressure exerted on these dams cannot be over emphasized. The study therefore examines the relationship between water depth and pressure on dam wall in five dams located at the Gbullung-West inland Valley Watershed of the Tolon-Kumbungu District, Ghana. A water level sensor HOBO U20 logger was installed in all five dams for the study period. Water levels were logged at 15 minutes interval on continuous basis for 12 months. Average annual drawdown for the various dams ranged from 0.97 m to 1.42 m. average dam drawndown’s were 1.16 m, 0.97m 1.42 m, 1.32 m and 1.01 m for dam 1, 1, 3, 4 and 5 respectively. The variation in water levels was mainly due to evaporation, domestic usage and animal watering. Dam pressure levels were 110.73kPa, 108.87kPa, 113.25 kPa, 112.33 kPs and 109.32kPs for dam 1, 2, 3, 4 and 5 respectively. The correlation coefficients of water depth and water pressure showed a strong relationship between the two. Correlation coefficients were 0.998, 0.969, 0.985, 0.992 and 0.969 for dam 1, 2, 3, 4 and 5 respectively. It was therefore realized that higher water depth resulted in higher water pressure exerted on dam dam wall. Proper constructional and dam wall management or maintenance practices should therefore be employed in order to avoid dam breaching.